true if

Excerpted from http://www.comptechdoc.org/os/linux/usersguide/linux_ugshellpro.htmlTestsThere is a function provided by bash called Test which returns a true or False value depending on the result of the tested Expression. It syntax is:Test

Judgment file:Workdir=/home/tmplocal_list_file= $WORKDIR/local.list#if no Local.txt file, generate a new oneif [!-F "$LOCAL _list_file"]; ThenTouch $LOCAL _list_fileFiNote: Be sure to have a space, to determine whether the file exists, if it does

If condition judgment1. Basic syntax:if [command]; ThenStatements that meet the criteria for executionFi2. Extended syntax:if [command];thenStatements that meet the criteria for executionelif [Command];thenStatements that meet the criteria for

Http://wenku.baidu.com/link?url=9Q9VU54XuvlN77urP1zwOLVMMrS2EFNx4HcvFizdPl-zQy3K_ Ipd3o-mdu4sbihezumnq0blbwhusuaol_y6quvkxtgjiaem9gq9i-jb5_e Shell in the condition to determine if in the-Z to-D meaning 2011-09-05 [-a file] if the file The existence

Shell if judge commonly used in the green part, the tail part of the more do not understand. Reproduced from Baidu Library. [-A file] if FILE existence is true. [-B-file] True if file exists and is a block-specific file. [-C file] is true if file

[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file

[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file

If statement format:If condition then statements [elif condition then statements ...] [Else statements] fiThe syntax for the most streamlined if command is:if TEST-COMMANDS; then CONSEQUENT-COMMANDS; fiThe IF condition judgment statement

This article mainly introduced the shell script if condition judgment and the judgment condition summary, this article first gave the IF condition judgment the grammar, then gave the commonly used judgment condition summary, needs Friend can refer

Objective:no matter what programming language is inseparable from conditional judgment. The shell is no exception. Copy Code code as follows: If List Then Do something here Elif List Then Do another thing Else Do something

Java EE Development of various types of resources download list, the history of the most complete IT resources, personal collection summary. Objective: No matter what programming language is inseparable from conditional judgment. The shell is no

Startup script start.sh This script is used to start the project, log logs and PID#!/bin/shprg=" $" #$ A represents the current startup script # Get the true path of the file while[-H"$PRG"]; Dols= ' Ls-ld"$PRG"' link= ' Expr"$ls": ' .*-> \ (. *\) $"

The shell condition determines if the-Z to-D meaningShellfilestringless Terminal user[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if

From: http://m.jb51.net/article/56553.htm This article mainly introduced the shell script if condition judgment and the judgment condition summary, this article first gave the IF condition judgment the grammar, then gave the commonly used judgment

by Francis_hao Oct 1,2017This article extracts the Man Handbook from bashConditional expressionsThe conditional expression is composed of a composite command [[or] built-in command test and [used for testing file properties and string or numeric

The shell condition determines if the-Z to-D meaning[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E

[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file

[ -a file] is true if file exists. [ -b file] True if file exists and is a block special file. [ -c file] True if file exists and is a word special. [ -d file] True if file exists and is a directory. [ -e file] is true if file exists. [ -f file]

[] and test Both are the same, and the test expr and [expr] have the same effect on the command line.The three basic functions of test are to judge a file, judge a string, and judge an integer. Supports the use of "and or not" to concatenate

[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file